prosecution history estoppel bars Duramed’s allegations of infringement under the doctrine of equivalents

DURAMED PHARMACEUTICALS, INC. (NOW KNOWN AS TEVA WOMEN’S HEALTH, INC.), plaintiff-appellant, lost before the CAFC. At issue were claims of U.S. Patent 5,908,638 (“’638 patent”), which was directed to conjugated estrogen pharmaceutical compo- sitions for use in hormone replacement therapies.

Festo was cited:

The district court granted Paddock’s motion for summary judgment of noninfringement, holding that prosecu- tion history estoppel barred Duramed’s infringement allegations. Duramed, 715 F. Supp. 2d at 555-56. The district court first held that Duramed’s amendment adding the ethylcellulose limitation was substantially related to patentability and narrowed the scope of the asserted claims, thus triggering the presumption under Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 344 F.3d 1359, 1366-67 (Fed. Cir. 2003) (en banc) (“Festo IX”), that Duramed had surrendered all territory between the original and amended claim scope. Duramed, 715 F. Supp. 2d at 559-60.

Footnote 1 alluded to a "public availability" issue:

The district court did not consider Paddock’s re- maining pre-1998 articles based on Duramed’s claim that a bench trial would be necessary to determine if the 1995 “Manufacturing Chemist” article was publicly available in a university library and if the conference articles were actually distributed to the attendees. Id. at 561 n.8. The court concluded that these articles were not necessary to establish foreseeability. Id.

AND footnote 2 notes:

We disagree that there is a genuine issue of material fact on the public availability of an article published in a scientific journal three years before Duramed’s amendment. See, e.g., In re Lister, 583 F.3d 1307, 1312 (Fed. Cir. 2009).

Foreseeability was at issue:

Because during prosecution Duramed narrowed the scope of the ’638 patent’s claims in response to a prior art rejection, a presumption of prosecution history estoppel applies. See Festo IX, 344 F.3d at 1366-67. Nonetheless, Duramed may rebut that presumption by showing, inter alia, the “alleged equivalent would have been ‘unforesee- able at the time of the amendment and thus beyond a fair interpretation of what was surrendered.’” Id. at 1369 (quoting Festo VIII, 535 U.S. at 738). “[A]n alternative is foreseeable if it is disclosed in the pertinent prior art in the field of the invention. In other words, an alternative is foreseeable if it is known in the field of the invention as reflected in the claim scope before amendment.” Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 493 F.3d 1368, 1379 (Fed. Cir. 2007) (“Festo X”). Foreseeability is a question of law based on underlying issues of fact. Id. at 1375.

Of the outcome:

We agree with Paddock that Duramed failed to rebut the presumption of prosecution history estoppel based on unforeseeability. We first note that, to the extent that Duramed argues that foreseeability requires that PVA must have been known as an MBC for use with conju- gated estrogens, we have previously rejected such a re- strictive definition of the field of invention. See Schwarz Pharma, Inc. v. Paddock Labs., Inc., 504 F.3d 1371, 1377 (Fed. Cir. 2007).

AND

foreseeability does not re- quire such precise evidence of suitability. See Honeywell Int’l, Inc. v. Hamilton Sundstrand Corp., 523 F.3d 1304, 1312-13 (Fed. Cir. 2008). And even if the PCT disclosure indicates that PVA is less than ideal in some pharmaceu- tical uses as an MBC, it is still disclosed to be useful as such, and that renders it foreseeable for purposes of prosecution history estoppel. Foreseeability does not require flawless perfection to create an estoppel.